IDEA #3F8FE2 Meta-Fizeau interferometer and meta-lens for spectrometry, imaging and sensing. 25A0012

Key Words: multifunctional metasurfaces, holography, optical characterization, spectrometry, polarimetry, spectropolarimetry This disclosure features optical elements, systems and methods for interferometry and other applications involving detection and manipulation of frequency components of optical waveforms. The optical elements include one or more meta-material layers that define phase gradients along at least one direction of the layers, thereby functioning as dispersive components that cause different frequency components of an optical waveform to be spatially separated. The optical elements can be implemented in the form of a wedge or prism and integrated into optical systems. For example, in some embodiments, the optical elements function as (or are part of a system that functions as) a Fizeau interferometer. Optical elements and systems can include multiple meta-material layers to increase the spatial dispersion of frequency components of an optical waveform, and an input optical waveform can make multiple passes through one or more meta-material layers to enhance spatial dispersion of frequency components and measurement sensitivity. The invention serves as an interferometer similar in operation to the Fizeau Interferometer but leveraging metasurfaces and metamaterial concepts to enable a flat form factor. Fizeau interferometers are composed of two partially reflecting surfaces that would be parallel but for a small ‘wedge angle’. The two nearly parallel surfaces form an etalon with a spacer thickness that slowly changes spatially. Since thickness in an etalon specifies its spectral response, a Fizeau interferometer can be thought of as encoding a wide range of spectral responses into a single arrangement. Fizeau interferometers may be used as spectrometers, for testing the flatness of a test surface relative to a known reference surface, and for determining the Fresnel drag in moving liquids.